Multiple-skirt insulator



Feb. 24, 1931. K HAwLEY 1,794,111

MULTI PLE SKIRT INSULATOR Filed April 8. 1927 Patented Feb. 24, 1931 UNITED STATES PATENT OFFICE KENT A. HAWLEY, OF BALTIMORE, MARYLAND, ASSIGNOR T0 LOCKE INSULATOR COR- PORATION, 0F BALTIMORE, MARYLAND, A CORPORATION OF MARYLAND MULTIPLE-SKIRT INSULATOR Application filed April 8,

The invention relates to insulators, particularly those of the suspension type used 1n connection with high tension lines.

The principal object of the invention, generally stated, is to provide an insulator of the multiple skirt type or that variety in which upper and lower hoods are provided on a shank or body which takes the vertical strain, the essential feature being the provision of a novel method of mounting the sus pension elements whereby a plurality of the insulators may be connected in a string or chain. 7

I am aware that it has been proposed to provide insulators of this same general type in so far as the multiple skirts are concerned but '11 the ordinary constructions it has been customary to provide reduced extensions upon the ends of which are secured, as by cementing, metal caps having some form or other of connecting means. A disadvantage of this ordinary construction is that there is a large area of metal exposed between the successive units in a string or chain.

It is with the above facts in View that I have designed the present invention which has for a more specific objectthe provision of a multiple skirt insulator in which connecting members of pin or bolt form are embedded within the end portions and extend therein to such a degree that the outward bursting strains caused by the reaction of the bolts against the dielectric body will occur at the points where the hoods or skirts are located, the material at these locations being so thick and heavy as compared with other points that the material will be able to withstand the bursting strains, the insulator consequently having great strength and durability.

A further object of the invention is to provide an insulator of this character in which the insulator elements may be of the same nature as those used in the present suspension insulators of the cemented type, the coacting or adjacent elements being preferably constructed to provide ball and socket joints so that the minimum area of metal will be exposed between adjacent sections.

Another object of the invention is to provide an insulator of the character indicated which will possess the advantages enumerated without being more expensive or difficult to assemble and install, the entire structure being, moreover, extremely durable and efficient in service and consequently a general improvement in the art.

With the above and other objects and advantages in view, as will hereinafter appear, the invention preferably consists in the detailed construction and the arrangement, combination and location of parts to be hereinafter more fully described and claimed, and illustrated in the accompanying drawing in whichr The figure is a view partly in elevation and partly in section showing an insulator constructed in accordance with the invention.

Referring more particularly to the drawing, I have shown the insulator as comprising an elongated body or shank 1 upon which are provided hoods or skirts 2 which may be identical or simply more or less similar in regard to size and contour. These hoods are-preferably arranged comparatively close to the ends of the entire device and they may be formed integrally upon the shank or body 1, as by molding or casting or formed separately and subsequently attached, this detail being immaterial as far as the present invention is concerned especially as it is possible to form and assemble the parts in either manner. In insulators of this general type the undersurfaces of the hoods are preferably formed with alternating grooves and ribs 3 and 4 respectively to increase the leakage path and I find it also advisable to corrugate or ridge the periphery of the shank or body 1 as indicated at 5 not only for the purpose of further increasing the current leakage path but also for rendering the in sulator more or less self-cleaning when rain water impinges thereupon.

In accordance with the present invention each end portion of the insulator is cored out, bored or otherwise treated at some suitable stage in the manufacture to providea socket, recess or cavity 6 coaxial with the body, the inner end of each cavity being preferably somewhat enlarged as at 7 with ing compound such as asphaltum or the like its wall stepped, the steps being defined by frustoconical areas or portions 8 and 9 meeting at an angle.- The outer end of each socket is preferably somewhat flared. as indicated at 10 principally for the purpose of avoiding a sharp or feathery edge which would be difilcultto glaze. The insulator'as a. whole is of course treated in the-customary manner in so far as glazing and firing are concerned and it might be mentioned that if desired the walls of'the sockets 6 maybe left simply unglazed or sanded as is a common practice, this detail being likewise immaterial.

Located within the respective sockets 6 are pin or bolt members 11 and 12, the former of which is here shown as formed with a socket 13 and the latter with a ball headll,

the purpose being to permit connection of units in string orchain form as is customary in connection with high tension lines. There should of course be no limitation'as to the exact type of suspension elements, the particular variety disclosed being simply for purposes of illustration especially to bring out clearly that very'littlemetal need be exposed between successive units in a string. The bolts or pins 11 andl2 are shown as provided at their inner ends with stepped portions 15 as iscommon in pin construction, the stepped portions being arranged substantially opposite the frusto conical sur-' faces 8 at the inner ends of the-sockets. The pins or bolts maybe coated with asphaltum or the like throughout the portion 'of'their length located within the sockets as is also a common procedure and securing is effected by means of cement 16 of suitable type which is filled into the sockets so as to embed the pins or bolts therein. It. is preferable that the cement should not entirely fill the sockets so as to leave spaces at the outer ends thereof to be filled with some suitable seal indicated at 17, thepurpose of this sealing step being to exclude moisture and prevent the cement from absorbing it and swelling a consequence with resultant detriment to the porcelain body;

The insulator is of course used in identically the same manner as others of a similar type but it has the advantage that the pins or bolts will probably exert a more efiicient holdingaction than caps cemented exteriorly upon reduced end portions as is common practice. Quite naturally when a load is sus tained by an insulator constructed in this manner the inclination of the surfaces forming the steps 15 will exert an outward force upon the cement and this force will be transmitted to the porcelain of the body. This is inevitable but in viewof the fact that the stepped portions of the pins or bolts are located at points substantially opposite the centers of the hoods or skirts, or, more strictly speaking, at such points that the lines of outward force exerted by the stepped port ons are applied at the maximum thickness of dielectricmaterial, the materialwill be able to withstand the'bursting strains without breaking down. Actual experiment has demonstrated that an insulator, constructed in this manner is capable of sustaining heavy loads without any apparent impairment of eiiiciency, eit er from a mechanical or an "electrical viewpoint. The feature of leaving that l reservethe right tomake all such changes as will not depart from the spirit of the invention or the scope of .the claim hereunto, appended.

Having thus described the invention, I claim: y

An insulator comprising a dielectric. body of elongated form provided near its ends with enlargements constituting hoods, the body being formed in its ends with sockets g their inner ends enlarged and including frusto-conical wall portionsmeetingat angles, and suspension elements secured with in the sockets and having their endsformed with stepped portions substantially opposite and coacting with said frusto-conical wall portions, said wall portions and stepped portions being located approximately opposite the centers of the hoods whereby the radiating lines of force exerted by the stepped portions of the suspension elements under. load will be opposed by substantially the maximum thicknessof dielectric material.

In testimony whereof I atfix my signature. KENT A. IIAWVLEY. 

